Twin Engine Fighters

[spicmart]

Even though japanese war efforts were in a desperate state the fact that
the Ki-45 was produced until July 1945 might be seen as a testimony to the
soundness of the design. So the question is why would the Japanese give the powerful
engines to the Ki-83 when a proven design has been available? The Ki-83 is better
aerodynamically but is that enough to justify complicating things by introducing a
new aircraft?

 

[GregP]

At the state of the war they were in, only a quantum leap in SOMETHING would really do any good. So I'd say new fighters would get priority.

Same with the Germans. Once 1,000 bombers escorted by 700 fighters showed up overhead, only a Ta 152 or Me 262 / other jet / rocket would offer much of a chance to stem the tide at all. Building more of the same of what didn't get the job done would just be prolonging the inevitable.

Only a new plane with a quantum leap in SOMETHING would make a difference.

With what the Germans did to captured peoples, I'm sure Hitler KNEW he'd be hung or executed by firing squad. His suicide was an aviodance measure, and was undoubtedly just. Not sure taking everyone with him was justified, but I doubt Eva Braun would have been exempted from some type of justice, had she lived. The wife of a deposed and villified Emperor is not usually spared.

Same with the Japanese but, for some reason, we didn't elect to pursue that option. I have NO IDEA why Japanese war crimes were glossed over while some high-ranking Germans were executed. Fortunately, all these people are pretty much gone today except for a few rather senior individuals. Executing them now would be a bit like closing the door after the horses have left the barn. But ... and here's the rub ... there is no statute of limitations on murder in war or otherwise, as far as I know.

I don't think a Ki-45 with 2,200 HP would have done the trick. It could MAYBE be accomplished by 2,000 good pilots and a flock of F-86's, a whole LOT of jet fuel, and coupled with a new fleet ... and maybe not. By the end of the war we were prepared for most anything we encountered. The Allies could field a substantial force of Battleships, Heavy Cruisers, etc. even if Japan HAD a new fleet, and a few ultra-modern planes would have a hard time against tens of thousands of piston warplanes.

 

[Shortround6]

Sticking 2000hp engines in a KI 45 is going to be a bit difficult.

The KI-96 may have been a more practical option.

Twin 1500hp engines and a speed of 600kph at 6000 meters.

Possibility of production in early 1944?

 

[GrauGeist]

...Same with the Japanese but, for some reason, we didn't elect to pursue that option. I have NO IDEA why Japanese war crimes were glossed over while some high-ranking Germans were executed. Fortunately, all these people are pretty much gone today except for a few rather senior individuals. Executing them now would be a bit like closing the door after the horses have left the barn. But ... and here's the rub ... there is no statute of limitations on murder in war or otherwise, as far as I know...

Of the over 5,000 Japanese military personnel tried and convicted, 900 were executed, including Hideki Tojo, Iwane Matsui (Nanking), Heitaro Kimura (Allied POW torture/mistreatment) and so on...with the Cold War escelating, the trials became pushed to the back shelf as world events were developing.

 

[Koopernic]

Post war analysis of the Bf 110's performance during the BoB using actually loss data (not claims by pilots) show that it had an exchange ratio with the British fighter (Hurricane and Spitfire) of greater than 1:1 in its favour. Of course given the expense of the Bf 110 and its 2 crew this is not enough. In general the Bf 110 suffered from the same problems as the Bf 109, there were too few of them with too few pilots. Drop tanks would have improved the Bf 110 almost as much as the Bf 109 at the time.

The Bf 110 acceleration may have been limited but it handled well, its fire power was immense and accurate, few aircraft could survive getting in the sighs of this aircraft. Furthermore the rear gunner, radio operator, observer navigator must have immensely relieved the pilot. All of the pilots attention would be in the forward hemisphere, his view over the nose excellent and the rear gunner would have noticed most attempts to 'jump' the aircraft. They would have been seldom surprised.

The aircrafts power to weight ratio was simply insufficient, but had a suitable engine of appropriate power been available a single seat version should have been quite effective.

 

[pbehn]

Post war analysis of the Bf 110's performance during the BoB using actually loss data (not claims by pilots) show that it had an exchange ratio with the British fighter (Hurricane and Spitfire) of greater than 1:1 in its favour. Of course given the expense of the Bf 110 and its 2 crew this is not enough. In general the Bf 110 suffered from the same problems as the Bf 109, there were too few of them with too few pilots. Drop tanks would have improved the Bf 110 almost as much as the Bf 109 at the time.

The Bf 110 acceleration may have been limited but it handled well, its fire power was immense and accurate, few aircraft could survive getting in the sighs of this aircraft. Furthermore the rear gunner, radio operator, observer navigator must have immensely relieved the pilot. All of the pilots attention would be in the forward hemisphere, his view over the nose excellent and the rear gunner would have noticed most attempts to 'jump' the aircraft. They would have been seldom surprised.

The aircrafts power to weight ratio was simply insufficient, but had a suitable engine of appropriate power been available a single seat version should have been quite effective.

Thats strange and the opposite of what I have read...I will read again and reply.

 

[pbehn]

I pretty much agree, pbehn, but a twin with close-inboard engines might be fine. Once the P-38J came online with hydraulic assists for the ailerons, it could roll with alacrity. The Do 335 Pfeil probably had no rolling deficicncies other than sheer mass.

But in general, I must agree that mass out on the wings slows the roll, at least initially.

I know from personal experience that the tip tanks on a Cessna 310 make the roll a bit ponderous when they have fuel in them. I have no doubt that two 1,500-pound engines coupled with radiators and props would make at LEAST the initial roll breakout slow down considerably unless some specialy design features could be found to make the roll response faster.

Perhaps if they did something like eliminate the ailerons entirely and have the entire wing pivot like an aileron ... it might eliminate the issue. But it would surely bring issues of its own and, if it DID work, the singles would follow suit in a very short time and probably resestablish their roll superiority.

Another point is that although the torque of late WW2 single engined fighters was a problem in many situations take off and landing in terms of roll I believe it gave an advantage. Rolling with the engine torque is something a twin cannot do.

 

[parsifal]

what about those JAAF bomber conversions built specifically to go after high altitude B-29s. Japanese were never able to get them to work properly because they had problems with their engines and pressurization issues.....I was thinking specifically the bomber destroyer version of the Ki-67....there were some others, including one some year earlier of the betty bomber destroyer .....

 

[GregP]

Never really considered rolling with the torque as an advantage, but it certainly could be. I consider the better option is to cancel the torque, say with a contra-prop for a "single." But you are right, in the correct circumstances it could be an advnatage ... so a twin, if attacked, should probably always break so the single has to roll against the torque.

Hhhmmmm ... not a bad thing to consider.

 

[Shortround6]

What happens if the twin has both engines/props turning in the same direction?

 

[GregP]

I think it falls apart ...

Couldn't resist Shortround ... not aimed at you.

I think it would manifest itself ina slow yaw in one direction, but I'm not too sure if both are turning whether or not the rolls gets slower. I know one engine is critical and the other is not, but we all know that as wella s which one. But when both are turning, I'd think roll would be closer to right and left than a single, but maybe slightly slower one way than the other?

Every time I've done engine-out in a twin ... I've been concerned with keeping it straight and NOT rolling into the dead engine unless I throttle the good one back a bit.

 

[Just Schmidt]

Some months ago I made a post about partial rehabilitation of the Bf 110 in the bob, and got away With it. It was sparked by an article, and it seem appropriate to elaborate a little in this thread. It is written by Christer Bergström in swedish, though he has several works in English published. With Luck the translation into Norwegian hasn't crippled it too much.

It quotes both claims and confirmed losses. One problem in comparing kills between 109's and 110's is that it's not that easy to determine which of the types shot Down how many of the actual losses. It is to be expected that a gunner in a bomber on occasion also got in a Lucky shot.

He's principally following II/ZG 76 during some of the bob. As such, this is not an overview over all Bf 110 Activity in this, and that should be kept in mind. Never the less it's intersting enough, I'll pass on some of his findings in English. Whenever I use the term 'confirmed', it will refer to losses as repoerted by the enemy, not other Bf pilots.

Firstly, during the Battle of France II/ZG 76 claimed 85 victitories against 7 losses. 50 to 60 of those claims are confirmed. For comparison the average for bf 109 equipped units was 1:4.

According to Christer Göring advised fri jakt (a term I know in it's german form from later night fighters as freier jagd), whereas the Commanders Down the chain tied the fighters to Close escort. Probably both strategies was to some extent emplyed troughout. be that as it may, on 12th of august no Aircraft of II/ZG 76 was lost, they claimed 4 bristish Aircraft of the 27 reported of the day. 11 was confirmed as destroyed, 6 as damaged.

On the 13th II/ZG 76 claimed 4 hurricanes without loss. (The text is unclear on the status of these claims).

On 15th of august II/ZG 76 (With a strength of 16) on Close escort was engaged by several squdrons. 6 were shot down and 2 crashed on landing. They claimed 19 of the 39 victories of the day, actual British losses of the day were 17. V.(Z)/LG 1 had flown fri jakt, and claimed 11 against a loss of 1. Reportedly Gôring was furious and on the 19th of august issued the order: "Only a part of the fighters are to be used as Close escort. The main part must be used in fri jakt on >extended escort< (sorry' it's the best exprssion i can come up With. This is a translation from german to Swedish to Norwegian to English. I hope somebody can check on the german Sources that must be extant).

On 25th of august II/ZG 76 without losses shot Down 4 (status unclear).

On 30th of august II/ZG 76 reported 18 victories out of the days total of 29 claims, against 3 losses plus 1 crash landing. Actual British losses were 13.

On 31th of august a British report to 11th Group reads: "Our fighters tried to attack the bombers, but ivariably Me 110's showed up behind Our fighters, while the Me 109's stayed high without interfering". 4 victories (unclear status) against a loss of 1.

1st of september saw II/ZG 76 shooting Down 4 hurricanes (out of 8 claimed) of 85th squadron without losses. Sqadron leader Peter Townsend was among the downed pilots. The day after ZG 76 officially became the first squadron With 500 claimed victories.

During bob II/ZG 76 lost 18 against a claim of 102. That can be compared III/JG 26 which in august-sept claimed 93 against 23 losses.

Other episodes reoorded is on 29th of august 41 over The Netherlands 4 of II/ZG 76 fought 11 spitfires 19th squadron, who lost 4 without scoring.

On 29th of april 1944 a 110 G-4 piloted by major Jabs (a veteran of II/ZG 76) was attacked by 4 spitfires while going in to land at Arnhem. A sudden swing made the spitfires overpass, and 2 were shot Down before Jabs landed 110 was shot up upon him escaping.

I'm not sure if it was in a post abowe it was obseved that the 2d crew member of the 110 relieved the pilot in many ways, and crucially could scan the sky behind and abowe the Aircraft. If so, it bears reiterating that the 110 had the best rear view of any fighter in bob, conferring one tactical advantage.

I'm not suggesting that the abowe in any way proves the 110 as superior to the spitfire. Other units undoubtedly fared worse, but the comparison in claims With 109's is noteworthy. An experienced pilot who knew his aircraft seem to be able to achieve a lot. At least the 110 didn't fall out of the sky everytime a spitfire pilot spotted it. While the abowe is not the whole story, it supplies some numbers and dates to be checked for those interested in empirics, or the approximation to empirics that history should at least aspire to.

 

[Kryten]

The 110 was considered an easy target by the RAF, you have to put context to that however, if your attacking bombers and a 110 gets behind you your in as much trouble as if it was a 109, it however seems that it was when used as a fighter sweep the 110 became a liability, once bounced they had little recourse but to form a wheel and hope to defend themselves!

there are two very big disadvantages to a twin fighter, one is size, your nearly always going to be seen first, the second is weight, mass always handicaps any form of manoeuvre, it's insurmountable,at what point does the advantages, two engines for reliability, range, payload etc outweigh the disadvantages? that is surely down to mission?

 

[pbehn]

Never really considered rolling with the torque as an advantage, but it certainly could be. I consider the better option is to cancel the torque, say with a contra-prop for a "single." But you are right, in the correct circumstances it could be an advnatage ... so a twin, if attacked, should probably always break so the single has to roll against the torque.

Hhhmmmm ... not a bad thing to consider.

It has just occurred to me that in the many debates about the spitfire and mustang that a mustang combat with a griffon spitfire may see them both being able to out roll the other depending on the direction. I am not an avid reader of flight tests but some do quote substantial differences in roll rate depending on direction.

 

[pbehn]

What happens if the twin has both engines/props turning in the same direction?

I think most twin AC do have the props turning in the same direction it has a slight effect but easy to trim. The higher the performance the more the effect obviously.

 

[Shortround6]

Most did during WW II, and it did make a difference in handling when one engine went out, I was wondering if there was difference in roll (or a marked one) left or right when both engines were operating.

 

[GrauGeist]

The P/F-82 had counter-rotating engines to solve several performance issues. They also had to trade the engines to either side because the first trial installation robbed lift and made it nearly impossible to take off.

The P-38 also had "handed" engines.

 

[pbehn]

The P/F-82 had counter-rotating engines to solve several performance issues. They also had to trade the engines to either side because the first trial installation robbed lift and made it nearly impossible to take off.

The P-38 also had "handed" engines.

The Hornet had similar problems

De Havilland tried props that rotated outward at the tops of their arcs (as in the P-38 Lightning),[6] but this configuration blanketed the fin and reduced rudder effectiveness at low speeds, compromising ground handling; on production Hornets the conventionally rotating Merlin 130 was on the port wing with the Merlin 131 on the starboard.[7]

 

[GregP]

Interestingly enough, the otiginal engine in the original XP-38 turned with the top of the props turning inward. The XP-38 suffered from a slight but noticable vibration and they switched engines. It eliminated the vibration and all subsequent P-38's with handed engines had the top of the prop tips turning outward ... which is a bit backwards from conventional thinking perhaps, but works.

There is no "cricital engine" because BOTH engines turn away from the center fuselage ... so engine-out situations handle the same way but in opposite directions.

It's possible they might have found out the same thing on the XP-82, but it never got airborne with normal, inward turning prop tips, so they had nothing to compare it with when it flew.

 

[drgondog]

Just the opposite for XP-82.

The XP-82 original layout had the props rotating from top tip Outboard, then inboard and upwards toward center wing section. The upwash into the center wing section, combined with the normal upwash as the AoA was increased (attempted take off) created a local inboard wing stall.

Changing the rotation to have tip at top rotate downward over the wing section cancelled the problem out.